The present invention generally pertains to thermal energy conversion systems and is particularly directed to an improvement in ocean thermal energy conversion systems.
In typical closed cycle ocean thermal energy conversion systems warm surface water is used to heat a working fluid with a low boiling point. Ammonia is a typical working fluid. The fluid is heated in a boiler. Vapor is then cooled by frigid water that is drawn up from deep in the ocean. The vapor condenses, and is pressurized and returned to the boiler; and the cycle is repeated.
Heretofore, it has been believed that ocean thermal energy conversion systems must be deployed in at least sub-tropical waters in order to obtain a large enough temperature differential within the ocean to provide a system that is sufficiently efficient to warrant commercial development.
Another concern with close-cycle ocean thermal energy conversion systems is the cost of heat exchangers that typically are used to transfers heat to the working fluid.
A concern with typical open cycle ocean thermal energy conversion systems is a requirement for bulky tanks having heavy walls so as to enable the sea water to be evaporated at a low pressure in relation to ambient or atmospheric pressure.